1. Field of the Ivention
The present invention relates to a flux for brazing especially silver brazing which is used for brazing a difficulty brazable metal such as sintered tungsten alloys or stainless steels.
2. Description of the Prior Arts
It has been well known that a tungsten or chromium component is oxidized to form its refractory metal oxide film having high melting point on a surface of the metal substrate during the heating in the silver brazing for the metal substrate such as sintered tungsten alloys or stainless steels, whereby its silver brazability is remarkably inferior. It has been proposed to improve the brazability by a brazing in a reducing atmosphere or a surface coating in a pretreatment.
In such cases, there are disadvantages that serious labour works are required for dew point control for the brazing in the reducing atmosphere improvement of reliability in the pretreatment and quality control in the brazing, however the characteristic of the resulting brazed part is not satisfactory.